Well, first you should have the isAttacking boolean to be set on your character blueprint, not on the anim blueprint cause its not part of the animation functionality, just do it on the key press event, for example
Second, check your collision presets, you have to make the weapon overlap the pawn object, and be sure that your character has the type “pawn” set on its collision presets (in the character this should be on the capsule component collision presets)
To debug, add a print string node on the onBeginOverlap to see if the problem is on the collision sets or on the hit handlign of your functions
Greetings,
- Nes